As well known in the art, washing machines for washing clothes are designed to absorb vibration generated by a tub in washing by supporting the tub with four-point dampers, that is, the dampers supporting the tub of washing machines reduce vibration generated by the tub rotating by absorbing it and provide retaining force for supporting the tub, such that there is no need of additional retaining members such as a suspension.
Dampers supporting a damper in washing machines were designed to attenuating front-rear movement of a load elastically supported by a spring with oil and a spring in the related art, but the dampers in the washing machines cannot efficiently absorb and reduce vibration when large and small loads are applied to the tub rotating and generate large noise, so the washing machines operate with noise.
Further, the vibration depends on the weight of the clothes to be washed and the operations of changing the damping force are unclear and influence each other, such that it is difficult to achieve complete attenuation of vibration due to large and small loads.